Is your chart from last night? If so, here’s what mine was doing over the same period for comparison:
The internal temperature is dropping from 18° at about 11pm when heating is “set back”, down to 16° at about 3am. The room stat calls for 6 short bursts of heat (at lower flow temps) which keeps the internal temp level until it switches up a gear at 6am, running continuously for 3 hours at 1.7 kW. By 9am it’s back up to 18° and goes back to intermittent cycles.
That 60% more heat put into my house compared to yours (assuming its the same period), though it looks like the outside temperature here was lower (measurements from local weather station).
Maybe I need to worry less about letting the house go “cold” over night. I know that I haven’t quite figured out the optimum heating strategy yet, so will continue to try out other ideas. Only got a properly working heat meter yesterday, so can now get some decent experiments going.